have therefore to apply the motions of the Aether medium to the solar
system, and by so doing reveal the physical explanation of all Kepler's
Laws, in the same way that Newton revealed their correctness from the
mathematical standpoint. Let us review the conception of the solar
system as given in Art. 99, so that we may be able to proceed from that
physical conception of a stationary solar system to a moving system.

Thus we see the sun in a stationary system occupying exactly the centre
of that system. The solar energies are in full play, generating
electro-magnetic Aether waves which are radiated forth into space with
the velocity of light. Then, as there is given to the sun a rotatory
motion on its axis, that rotatory motion imparts to the gravitating
aetherial medium a circulatory or rotatory motion which spreads out
through space with ever-increasing intensity.

By their radiating motion the Aether waves would repel all planets from
their central body, the sun, if they were not counterbalanced by the
centripetal force; and the two forces, the centrifugal and the
centripetal forces, find their equilibrium at the mean distance of each
planet, thus fixing and regulating permanently the distance and orbit of
each planetary world.

At the same time, the rotatory motion of the electro-magnetic Aether
currents, according to the second law of motion, would act on the
planets by their kinetic or moving energy, and so circle them round the
sun, their controlling centre. As long as the sun was quite stationary,
while still possessing a rotation on its axis, if such a thing were
possible, so long would the conception of the ancients be fulfilled, and
the rotation of all the planets would be strictly circular in form, and
their orbits would be that of a circle only, as proved by Sir W. R.
Hamilton (Art. 99).

[Illustration: Fig: 24.]

But, as is well known, the sun itself possesses an orbital motion of its
own, so that, while all the associated planetary system is revolving
round it, the sun with all that system is being carried along through
space in an orbit which is also elliptic in form, as we shall see later
on.

According to Herschel, the sun is moving towards the constellation of
Hercules with a velocity of about 18,000 miles per hour, and the problem
to be faced is, what is the effect of the sun's orbital velocity upon
the circular motion of the planets? By solving that problem, we shall
arrive at a physical conc